J. Bier

MORPHOLOGY OF THE DEVELOPMENT OF THE SAGITTAL SUTURE OF MICE

Abstract Syndesmotic sutures of the skull are formed by dense connective tissue and called ”open”; they are ”closed” by formation of a synostosis between adjacent bones. Open sutures are considered as areas of growth and as hinges. The importance of open sutures during the period of skull growth is reflected by pathological situations in which premature closure of the sutures occurs. As alterations of the FGF receptor have been reported in genetical disorders accompanied by premature suture closure (Bellus et al. 1996), the role of fibroblasts and connective tissue in the development of the sagittal suture of mice has been investigated by light and electron microscopy. Morphological changes of the sagittal suture at the following stages are reported: at embryonic day 18, days 1, 5, 9, 14, 20, 26, 28 after birth and in adult mice. Two skulls per stage were investigated. Early osteogenesis appeared in a thin plate, followed by a second plate underneath the first one. Both were separated by blood vessels. In general, vascularization preceded desmoid mineralization; the space around blood vessels was occupied by non-bone-forming cells leaving cavities for the presumptive bone marrow. Mineralization of the collagen-rich osteoid at the mineralizing rim of the bone plates was accompanied by apoptoses and cell disintegration. Newly formed bone was immediately covered by osteoblasts forming a sheet of bone-lining cells. At day 9, the double-layered bone plates of both sides reached the median area of the skull but were separated by non-mineralizing, collagen-rich connective tissue. From day 14 onwards, the bone plates thickened. Bone apposition, recognizable by the formation of collagen-rich osteoid and proceeding from day 14 pp onwards, occurred mainly at the outer and inner surfaces of the calvariae, but neither at bone marrow surfaces nor at the medial edges of the parietal bones. These opposite bone faces showed fewer osteoblasts and bone-lining cells, but an increased number of fibroblasts. Tendon-like collagen bundles connected both bone plates of the open suture of day 26 pp as well as in the adult mice, whereby synostotically closed areas alternated. Formation of an open, syndesmotic suture can, therefore, be described as a transition of bone-forming tissue into a bone-tendon junction. The results indicate the importance of the replacement of osteoblasts by fibroblasts at the sutural front of the bone plates in order to prevent a premature suture closure.

Reconstruction of the contracted ocular socket with free full-thickness mucosa graft

Patients who have undergone enucleation of the eye can be treated with glass eye prostheses, provided retention is adequate. Inadequate retention due to contraction of the conjunctival mucosa is a common problem which frequently affects the lower fornix first. This can be corrected using a free full-thickness buccal mucosa graft. Indications, operative procedures and postoperative results are presented.

Computed tomographic study of bone availability for facial prosthesis-bearing endosteal implants

In a computed tomographic study, 56 patients with facial defects were examined to assess the availability of bone for extraoral Brånemark implants (3 or 4 mm long, 3.75 mm diameter) to bear facial prostheses. Bone depths were determined in the auriculotemporal (2-8 mm), infraorbital (0-10 mm), lateroorbital (8-14 mm), supraorbital (1-14 mm) and medioorbital (1-6 mm) areas as well as at the base of the nasal skeleton (1-5 mm). The low values for the supraorbital and infraorbital areas were determined at the points closest to the frontal- and maxillary sinuses, respectively. Implantation in these areas would be permissible only under certain conditions. The very thin osseous structures of the nasal region also present problems for implants. In the auriculotemporal region, the bone width is always sufficient, but at the orbital margin it can vary from 3 to 8 mm. The three-year success rates for implant survival were found to be 100% and 85.8% respectively for auricular and orbital defects. No serious skin complications were seen. Six patients (10.7%) required secondary corrective surgery in a total of 13 implant areas.

Camouflage in head and neck region – a non-invasive option for skin lesions

The technique of camouflage, a non-invasive procedure to correct flaws in the texture and colour of the facial skin, is presented. The acceptance and use of camouflaging by 52 patients with different diagnoses are presented. The advantages of camouflaging are discussed in comparison to medical tattooing.

A method for the bony and dental reconstruction of the maxilla in dentate patients.

Reconstruction was carried out on eleven patients using a vascularized full thickness calvarial bone flap following partial maxillectomy. The donor site was covered with a split calvarial bone graft. Intraorally a mucosal transposition flap was used to cover the graft. Six months later implants were inserted and were allowed to heal for three months before dental rehabilitation began. No serious complications were encountered.

Contrast-enhanced high resolutionmagnetic resonance imaging of skin tumours

Abstract Purpose: To evaluate the use of Gd-DTPA in imaging epithelial skin tumours and tumour-like lesions, 45 benign and 18 malignant skin tumours were prospectively examined by high resolution magnetic resonance imaging (MRI) at 1.5 T using a 2.5 cm surface coil. Methods: For tumour assessment, transverse plain and contrast-enhanced scans (0.1 nunol kg −1 Gd-DTPA) were performed (TR 500 ms, TE 25 ms, three acquisitions, 256 × 256 matrix, FOV 2.5 cm). Results: Contrast enhancement (CE) was quantitatively determined as the percentage enhancement of signal intensity. Histological findings were correlated using a Wilcoxon test ( P Conclusions: Malignant tumours could not be differentiated from benign lesions by contrast enhancement. MRI using Gd-DTPA does not differentiate skin tumour types.

Rezidivierender Weichteiltumor des Untergesichts

Der 19 Monate alte Patient wurde mit einer ausgedehnten Raumforderung der Kopf-Hals-Region wegen Schluckbeschwerden, Inappetenz und leichter Atemnot in der Mund-Kiefer-Gesichtschirurgie vorgestellt. Klinisch bestanden eine ausgeprägte Schwellung des Untergesichts und eine Makroglossie. Der weitere körperliche Untersuchungsbefund war unauffällig; die üblichen laborchemischen Parameter befanden sich im Normbereich. Bereits 9 Tage nach der Geburt war alio loco eine große submandibuläre Raumforderung operiert worden.